Air conditioning systems for vehicles, comprising such air conditioning systems, and methods for driving hybrid compressors of such air conditioning systems

ABSTRACT

An air conditioning system for a vehicle includes a compressor. The vehicle includes a first drive source and the compressor includes a second drive source. The compressor is driven by the first drive source or the second drive source, or a combination thereof, and the second drive source includes an electrical power supply. The air conditioning system also includes a controller for selecting between the first drive source and the second drive source, such that when the compressor is active, the first drive source drives the compressor except when the vehicle is operating in a predetermined mode, a voltage of the electrical power supply is greater than or equal to a minimum electrical power supply voltage, and an amount of electric power consumed by the second drive source is less than a maximum electric power. For example, the predetermined mode may be an idle-stop mode.

This application is a continuation of U.S. patent application Ser. No.10/465,579, filed Jun. 20, 2003, now U.S. Pat. No. 6,786,055, which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to air conditioning systems foruse in vehicles, vehicles comprising such air conditioning systems,methods for driving a hybrid compressor of such air conditioningsystems. In particular, the present invention is directed towardsvehicles, air conditioning systems, and methods for driving a hybridcompressor, in which a drive source of the hybrid compressor switchesfrom an electric drive motor of the hybrid compressor to an engine ofthe vehicle, when predetermined conditions are satisfied.

2. Description of Related Art

Known hybrid vehicles include a first drive source, e.g., an engine, andan air conditioning system. Such known air conditioning systems, such asthe air conditioning system described in U.S. Pat. No. 5,867,996,include a hybrid compressor, and the hybrid compressor includes a seconddrive source, e.g., an electric motor, and an electrical power supply,e.g., a battery, for the second drive source. The hybrid compressor maybe driven by the first drive source or the second drive source, or both.Specifically, the first drive source drives the hybrid compressor whenthe first drive source is engaged, and the second, drive source drivesthe hybrid compressor when the first drive source is disengaged. Assuch, whether the first drive source or the second drive source drivesthe hybrid compressor depends on whether the first drive source isengaged or disengaged. Nevertheless, when the voltage of the electricalpower supply is less than a predetermined voltage, or when the amount ofpower consumed by the second drive source is greater than apredetermined amount of power, the ability of the air conditioningsystem to deliver sufficiently cooled air or sufficiently heated air toan interior of the vehicle is reduced. Moreover, the driving force ofthe second drive source may be insufficient to drive other components ofthe air conditioning system, e.g., a blower.

SUMMARY OF THE INVENTION

Therefore, a need has arisen for air conditioning systems which overcomethese and other shortcomings of the related art. A technical advantageof the present invention is that when predetermined conditions relatedto the voltage of the electrical power supply or the amount of powerconsumed by the second drive source, or both, are satisfied, the drivesource of the compressor switches from the second drive source to thefirst drive source.

According to an embodiment of the present invention, an air conditioningsystem for a vehicle comprises at least one compressor. The vehiclecomprises a first drive source, and the at least one compressorcomprises a second drive source. The at least one compressor is drivenby the first drive source or the second drive source, or a combinationthereof, and the second drive source comprises an electrical powersupply. The air conditioning system also comprises means for selectingbetween the first drive source and the second drive source, e.g., acontroller, such that when the at least one compressor is active, atleast the first drive source drives the at least one compressor exceptwhen the vehicle is operating in at least one predetermined mode, avoltage of the electrical power supply is greater than or equal to aminimum electrical power supply voltage, and an amount of electric powerconsumed by the second drive source is less than a maximum electricpower. For example, the at least one predetermined mode may be anidle-stop mode.

According to another embodiment of the present invention, an airconditioning system for a vehicle comprises at least one compressor. Thevehicle comprises a first drive source, and the at least one compressorcomprises a second drive source. The at least one compressor is drivenby the first drive source or the second drive source, or a combinationthereof, and the second drive source comprises an electrical powersupply. The air conditioning system also comprises means for selectingbetween the first drive source and the second drive source, e.g., acontroller, such that when the at least one compressor is active, atleast the first drive source drives the at least one compressor exceptwhen the vehicle is operating in at least one predetermined mode, anamount of electrical power delivered by the electrical power supply tothe second drive source is greater than or equal to a minimum electricalpower, and an amount of electric power consumed by the second drivesource is less than a maximum electric power. For example, the at leastone predetermined mode may be an idle-stop mode.

According to yet another embodiment of the present invention, an airconditioning system for a vehicle comprises at least one compressor. Thevehicle comprises a first drive source, and the at least one compressorcomprises a second drive source. The at least one compressor is drivenby the first drive source or the second drive source, or a combinationthereof, and the second drive source comprises an electrical powersupply. The air conditioning system also comprises means for selectingbetween the first drive source and the second drive source, e.g., acontroller. Moreover, the means for selecting is adapted to select atleast the first drive source at least when the at least one compressoris active and an amount of electric power consumed by the second drivesource is greater than or equal to a maximum electric power. In anotherembodiment of the present invention, the means for selecting also isadapted to select at least the first drive source at least when avoltage of the electrical power supply is less than a minimum electricalpower supply voltage, or when an amount of electrical power delivered bythe electrical power supply to the second drive source is less than aminimum electrical power, or both.

According to still another embodiment of the present invention, avehicle comprises a first drive source and an air conditioning system.The air conditioning system comprises at least one compressor comprisinga second drive source. The at least one compressor is driven by thefirst drive source or the second drive source, or a combination thereof,and the second drive source comprises an electrical power supply. Theair conditioning system also comprises means for selecting between thefirst drive source and the second drive source, e.g., a controller, suchthat when the at least one compressor is active, at least the firstdrive source drives the at least one compressor except when the vehicleis operating in at least one predetermined mode, a voltage of theelectrical power supply is greater than or equal to a minimum electricalpower supply voltage, and an amount of electric power consumed by thesecond drive source is less than a maximum electric power. For example,the at least one predetermined mode may be an idle-stop mode.

According to still yet another embodiment of the present invention, avehicle comprises a first drive source and an air conditioning system.The air conditioning system comprises at least one compressor comprisinga second drive source. The at least one compressor is driven by thefirst drive source or the second drive source, or a combination thereof,and the second drive source comprises an electrical power supply. Theair conditioning system also comprises means for selecting between thefirst drive source and the second drive source, e.g., a controller, suchthat when the at least one compressor is active, at least the firstdrive source drives the at least one compressor except when the vehicleis operating in at least one predetermined mode, an amount of electricalpower delivered by the electrical power supply to the second drivesource is greater than or equal to a minimum electrical power, and anamount of electric power consumed by the second drive source is lessthan a maximum electric power. For example, the at least onepredetermined mode may be an idle-stop mode.

According to a further embodiment of the present invention, a vehiclecomprises a first drive source and an air conditioning system. The airconditioning system comprises at least one compressor comprising asecond drive source. The at least one compressor is driven by the firstdrive source or the second drive source, or a combination thereof andthe second drive source comprises an electrical power supply. The airconditioning system also comprises means for selecting between the firstdrive source and the second drive source, e.g., a controller. Moreover,the means for selecting is adapted to select at least the first drivesource at least when the at least one compressor is active and an amountof electric power consumed by the second drive source is greater than orequal to a maximum electric power. In another embodiment of the presentinvention, the means for selecting also is adapted to select at leastthe first drive source at least when a voltage of the electrical powersupply is less than a minimum electrical power supply voltage, or whenan amount of electrical power delivered by the electrical power supplyto the second drive source is less than a minimum electrical power, orboth.

According to a still a further embodiment of the present invention, amethod for driving at least one compressor of an air conditioning systemof a vehicle is provided. The vehicle comprises a first drive source,and the air conditioning system comprises the at least one compressor.The at least one compressor comprises a second drive source, and thesecond drive source comprises an electrical power supply. Moreover, theat least one compressor is driven by the first drive source or thesecond drive source, or a combination thereof. The method comprises thesteps of determining whether the vehicle is operating in at least onepredetermined mode, e.g., an idle-stop mode, and activating the seconddrive source when the vehicle is operating in the at least onepredetermined mode. The method also comprises the steps of determiningwhether an amount of electric power consumed by the second drive sourceis greater than or equal to a maximum electric power, and switching thedrive of the at least one compressor from the second drive source to thefirst drive source when the amount of electric power consumed by thesecond drive source is greater than or equal to the maximum electricpower.

Other objects, features; and advantages will be apparent to persons ofordinary skill in the art from the following detailed description of theinvention and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, the needssatisfied thereby, and the objects, features, and advantages thereof,reference now is made to the following description taken in connectionwith the accompanying drawings.

FIG. 1 is a schematic diagram of an air conditioning system according toan embodiment of the present invention.

FIG. 2 is a flow chart depicting an operation of the air conditioningsystem of FIG. 1 according to an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention and their features andadvantages may be understood by referring to FIGS. 1 and 2, likenumerals being used for like corresponding parts in the variousdrawings.

Referring to FIG. 1, an air conditioning system 100 for a vehicle (notshown) according to an embodiment of the present invention is depicted.Air conditioning system 100 may comprise a hybrid compressor 4 and arefrigeration circuit 1. Hybrid compressor 4 may be a variabledisplacement type compressor, a swash plate type compressor, a rotarytype compressor, a scroll type compressor, or the like. In anembodiment, the vehicle may comprise a first drive source 2, e.g., anengine, and hybrid compressor 4 may comprise a second drive source 5,e.g., an electric motor. In this embodiment, hybrid compressor 4 may bedriven by first drive source 2, second drive source 5, or both. Thedriving force of drive source 2 may be transmitted to hybrid compressor4 via an electromagnetic clutch 3 attached to hybrid compressor 4.

In another embodiment, hybrid compressor 4 may be similar to hybridcompressors described in U.S. Pat. Nos. 6,247,899 and 6,375,436. Forexample, hybrid compressor 4 may comprise, a first compression mechanism(not shown) and a second compression mechanism (not shown).Specifically, first drive source 2 may drive the first compressionmechanism, and second drive source 5 may drive the second compressionmechanism. Moreover, air conditioning system 100 may comprise means forselecting whether first drive source 2 or second drive source 5, orboth, drives hybrid compressor 4. For example, the means for selectingmay comprise a controller 15, and first drive source 2 and second drivesource 5 may operate selectively or simultaneously in response toelectrical, mechanical, or electro-mechanical control signals fromcontroller 15. The vehicle also may comprise electromagnetic clutch 3for transmitting a rotational force from first drive source 2 to a driveshaft (not shown) of hybrid compressor 4. In this embodiment, the driveshaft may comprise a first portion and a second portion. Specifically,first drive source 2 may drive the first portion of the drive shaft viaelectromagnetic clutch 3, and second drive source 5 may drive the secondportion of the drive shaft in response to the control signals fromcontroller 15.

In another embodiment, hybrid compressor 4 may be similar to the hybridcompressor described in U.S. patent application Ser. No. 10/235,802. Forexample, hybrid compressors 4 may comprise a first drive shaft and asecond drive shaft. Moreover, first drive source 2 may drive the firstdrive shaft via electromagnetic clutch 3, and second drive source 5 maydrive the second drive shaft via controller 15. In another example, airconditioning system 100 may comprise a pair of hybrid compressors 4.Specifically, a first of hybrid compressors 4 may comprise the firstdrive shaft, and a second of hybrid compressors 4 may comprise thesecond drive shaft. Moreover, first drive source 2 may drive the firstdrive shaft via electromagnetic clutch 3, and second drive source 5 maydrive the second drive shaft via controller 15.

In any of the above described embodiments of the present invention,refrigeration circuit 1 may comprise a plurality of refrigeration tubes,and a refrigerant may be circulated within refrigeration circuit 1 viathe refrigeration tubes. Refrigerant circuit 1 may comprise hybridcompressor 4, a condenser 6; a receiver 7; an, expansion valve 8; and anevaporator 9. Hybrid compressor 4 may be connected operationally tocondenser 6, and condenser 6 may be connected operationally to receiver7. Receiver 7 may be connected operationally to expansion valve 8, andexpansion valve 8 may be connected operationally to evaporator 9.Moreover, evaporator 9 may be connected operationally to hybridcompressor 4; such that hybrid compressor 4, condenser 6, receiver 7,expansion valve 8, and evaporator 9 form a closed, refrigerationcircuit. In operation, hybrid compressor 4 may receives refrigerant gasfrom evaporator 9 and also may compress that refrigerant gas.Compressing the refrigerant gas may increase a temperature of therefrigerant gas and also may increase a pressure of the refrigerant gas.Hybrid compressor 4 may pass the compressed refrigerant gas to condenser6. When the compressed refrigerant gas flows through condenser 6, atleast a portion of the refrigerant gas may condense into a liquidrefrigerant. Moreover, condenser 6 may pass the condensed refrigerant toreceiver 7, and receiver 7 may divide the condensed refrigerant into aliquid refrigerant portion and a refrigerant gas portion. Receiver 7 maypass the liquid refrigerant portion of the refrigerant to expansionvalve 8, which may decrease the pressure of the liquid refrigerant. Whenexpansion valve 8 reduces the pressure of the liquid refrigerant,expansion valve 8 may pass the refrigerant to evaporator 9, and mix therefrigerant with air dispensed by blower 12, which may evaporate theliquid refrigerant into a refrigerant gas. The refrigerant gas then maybe passed to hybrid compressor 4.

Air conditioning system 100 also may comprise a heater core 11positioned at a downstream side of evaporator 9, and an air mix damper10 formed between the downstream side of evaporator 9 and an upstreamside of heater core 11. Air mix damper 10 may be driven by a servo motor(not shown). The movement of air mix damper 10 may control a volume ofair capable passing through heater core 11 via evaporator 9, which maycontrol the air temperature within the interior of the vehicle.Moreover, blower 12, evaporator 9, air mix damper 10, and heater core 11may be positioned within an air duct 13. Air conditioning system 100also may comprise a first discharge port 21, a second discharge port 22,and a third discharge port 23, and discharge ports 21-23 may bepositioned at a downstream side of air duct 13. For example, firstdischarge port 21 may be formed above third discharge port 23, andsecond discharge port 22 may be formed between first discharge port 21and third discharge port 23. Moreover, first discharge port 21 may beused during a DEFROST mode, second discharge port 22 may be used in aVENT mode, and third discharge port 23 may be a FOOT mode. Such modesmay determine the source from which the air entering the interior of thevehicle is drawn, or the direction in which the entering air blows, orboth.

A temperature sensor 14 for measuring a temperature T_(eva) of airdispensed from evaporator 9 may be positioned between evaporator 9 andheater core 11. Temperature sensor 14 also may be operationallyconnected to controller 15. Specifically, temperature sensor 14transmits a first signal 16 a to controller 15 indicating a value ofT_(eva). In an embodiment of the present invention, the vehicle also maycomprise an electrical power supply (not shown), e.g., a battery, forsecond drive source 5, and controller 15 may receive a second signal 16b from the electrical power supply indicating a voltage B_(t) of theelectrical power supply. Controller 15 also may receive a third signal16 c indicating whether air conditioning system 100 currently isoperating, and a fourth signal 16 d indicating an amount of electricpower consumed by second drive source 5. Moreover, controller 15 mayreceive a fifth signal 16 e indicating whether the vehicle is in anidle-stop mode. An idle-stop mode occurs when the vehicle's speed isless than a predetermined speed, e.g., about zero kilometers per hour,during vehicle operation. Based on first signal 16 a, second signal 16b, third signal 16 c, fourth signal 16 d, or fifth signal 16 e, or acombination thereof, controller 15 may generate a first control signal17 for controlling a rotational speed of second drive source 5, and asecond control signal 18 for controlling the engagement anddisengagement of electromagnetic clutch 3.

Specifically, when second drive source 5 drives compressor 4,electromagnetic clutch 3 may be disengaged, and first control signal 17may be transmitted to second drive source 5 to control the rotationalspeed of second drive source 5. Nevertheless, when first drive source 2drives compressor 4, first control signal 17 may be deactivated, secondcontrol signal 18 may be transmitted to electromagnetic clutch 3 or acontroller thereof (not shown), and electromagnetic clutch 3 may beengaged. In another embodiment of the present invention, first drivesource 2 and second drive source 5 may operate simultaneously. Moreover,based on temperature T_(eva) of air dispensed from evaporator 9,controller 15 may select the rotational speed of second drive source 5,or determine whether to engage or disengage electromagnetic clutch 3.

Referring to FIG. 2, an operation 200 of air conditioning system 100according to an embodiment of the present invention is depicted. In step205, air conditioning system 100 transitions from active to inactive,i.e., is activated, and controller 15 receives third signal 16 c.Moreover, in step 210, temperature sensor 14 measures temperatureT_(eva) of air dispensed from evaporator 9, and transmits first signal16 a to controller 15. In step 215, controller 15 compares temperatureT_(eva) to a predetermined temperature and transmits second controlsignal 18 to electromagnetic clutch 3. For example, when temperatureT_(eva) is greater than or equal to the predetermined temperature, firstdrive source 2 drives compressor 4. Similarly, when temperature T_(eva)is less than the predetermined temperature, compressor 4 remainsinactive or transitions from active to inactive if compressor 4previously was active. In an embodiment, the predetermined temperaturemay be about 4° C., and temperature sensor 14 may have an accuracy ofabout ±1° C. As such, when temperature T_(eva) is greater than or equalto about 4° C., first drive source 2 may drive compressor 4, and whentemperature T_(eva) is less than or equal to about 3° C., compressor 4remains inactive or transitions from active to inactive if compressor 4previously was active. In step 226, controller 15 receives fifth signal16 e, and determines whether the vehicle is in the idle-stop mode, i.e.,when the vehicle's speed is less than the predetermined speed duringvehicle operation. If the vehicle currently is not in the idle-stopmode, the operation of air conditioning system 100 returns to step 210.Nevertheless, if the vehicle currently is in the idle-stop mode, theoperation of air conditioning system 100 proceeds to step 225.

In step 225, first drive source 2 transitions from engaged to disengagedvia electromagnetic clutch 3, and second drive source 5 transitions fromdisengaged to engaged via first control signal 17. In step 230,temperature sensor 14 measures temperature T_(eva) of air dispensed fromevaporator 9, and transmits first signal 16 a to controller 15. In step235, controller 15 compares temperature T_(eva) to the predeterminedtemperature and transmits first control signal 17 to second drive source5. For example, when temperature T_(eva) is greater than or equal to thepredetermined temperature, second drive source 5 drives compressor 4.Similarly, when temperature T_(eva) is less than the predeterminedtemperature, compressor 4 remains inactive or transitions from active toinactive if compressor 4 previously was active. Moreover, in step 240,controller 15 receives second signal 16 b, and determines voltage B_(t)of the electrical power supply for second drive source 5.

In step 245, controller 15 determines whether voltage B_(t) is greaterthan a minimum electrical power supply voltage B_(t0), e.g., a voltagesufficient for second drive source 5 to drive hybrid compressor 4. Ifvoltage B_(t) is less than minimum electrical power supply voltageB_(t0), the operation of air conditioning system proceeds to step 260.In step 260, second drive source 5 transitions from engaged todisengaged via first control signal 17, and controller 15 transmitssecond control signal 18 to electromagnetic clutch 3, such that firstdrive source 2 transitions from disengaged to engaged viaelectromagnetic clutch 3. The operation of air conditioning system thenreturns to step 210.

Nevertheless, if in step 245 controller 15 determines that voltage B_(t)is greater than or equal to minimum electrical power supply voltageB_(t0), the operation of air conditioning system 100 proceeds to step250. In step 250, controller 15 receives fourth signal 16 d anddetermines the amount of electric power W consumed by second drivesource 5. In step 255, controller 15 determines whether the amount ofelectric power W consumed by second drive source 5 is greater than amaximum electric power W_(L). If the amount of electric power W consumedby second drive source 5 is greater than or equal to maximum electricpower W_(L), the operation of air conditioning system 100 returns tostep 260, e.g., second drive source 5 transitions from engaged todisengaged via first control signal 17, and controller 15 transmitssecond control signal 18 to electromagnetic clutch 3, such that firstdrive source 2 transitions from disengaged to engaged viaelectromagnetic clutch 3.

Nevertheless, if the amount of electric power W consumed by second drivesource 5 is less than maximum electric power W_(L), the operation of airconditioning system 100 proceeds to step 265. In step 265, controller 15receives fifth signal 16 e, and determines whether the vehicle still isin the idle-stop mode. When the vehicle still is in the idle-stop mode,then the operation of air conditioning system 100 returns to step 230,i.e., temperature sensor 14 measures temperature T_(eva) of airdispensed from evaporator 9, and transmits first signal 16 a tocontroller 15. However, if the vehicle is not in the idle-stop mode,then the operation of air conditioning system 100 returns to step 260,i.e., second drive source 5 transitions from engaged to disengaged viafirst control signal 17, and controller 15 transmits second controlsignal 18 to electromagnetic clutch 3, such that first drive source 2transitions from disengaged to engaged via electromagnetic clutch 3.

Thus, during vehicle operation, when (1) the vehicle is operating inidle-stop mode, (2) voltage B_(t) of the electrical power supply isgreater than or equal to minimum electrical power supply voltage B_(t0),and (3) the amount of electric power W consumed by second drive source 5is less than maximum electric power W_(L), second drive source 5 driveshybrid compressor 4. However, when during vehicle operation these threeconditions initially are satisfied, and subsequently one of these threeconditions no longer is satisfied, second drive source 5 may transitionfrom engaged to disengaged via first control signal 17, and controller15 may transmit second control signal 18 to electromagnetic clutch 3,such that first drive source 2 transitions from disengaged to engagedvia electromagnetic clutch 3.

While the invention has been described in connection with preferredembodiments, it will be understood by those skilled in the art thatvariations and modifications of the preferred embodiments describedabove may be made without departing from the scope of the invention.Other embodiments will be apparent to those skilled in the art from aconsideration of the specification or from a practice of the inventiondisclosed herein. It is intended that the specification and thedescribed examples are consider exemplary only, with the true scope ofthe invention indicated by the following claims.

1. An air conditioning system for a vehicle comprising a first drivesource, wherein the air conditioning system comprises: at least onecompressor comprising a second drive source, wherein the at least onecompressor is driven by the first drive source or the second drivesource, or a combination thereof, and the second drive source comprisesan electrical power supply; and means for selecting between the firstdrive source and the second drive source, such that when the at leastone compressor is active, at least the first drive source drives the atleast one compressor except when: the vehicle is operating in at leastone predetermined mode; and a voltage of the electrical power supply isgreater than or equal to a minimum electrical power supply voltage. 2.The air conditioning system of claim 1, wherein the at least onepredetermined mode comprise an idle-stop mode.
 3. The air conditioningsystem of claim 1, wherein the at least one compressor furthercomprises: a first compression mechanism driven by the first drivesource; and a second compression mechanism driven by the second drivesource.
 4. The air conditioning system of claim 1, wherein the firstdrive source comprises an engine, the second drive source comprises anelectric motor, and the electric power supply comprises a battery. 5.The air conditioning system of claim 1, further comprising: means fordetermining whether the vehicle is operating in an idle-stop mode; andmeans for determining whether the voltage of the electrical power supplyis greater than or equal to the minimum electrical power supply voltage.6. The air conditioning system of claim 1, further comprising: anevaporator; and means for determining whether a temperature of airdispensed from the evaporator is greater than a predeterminedtemperature, wherein the at least one compressor is inactive when thetemperature of air dispensed from the evaporator is less than thepredetermined temperature, and the at least one compressor is activewhen the temperature of air dispensed from the evaporator is greaterthan or equal to the predetermined temperature.
 7. An air conditioningsystem for a vehicle comprising a first drive source, wherein the airconditioning system comprises: at least one compressor comprising asecond drive source, wherein the at least one compressor is driven bythe first drive source or the second drive source, or a combinationthereof, and the second drive source comprises an electrical powersupply; and means for selecting between the first drive source and thesecond drive source, such that when the at least one compressor isactive, at least the first drive source drives the at least onecompressor except when: the vehicle is operating in at least onepredetermined mode; and an amount of electrical power delivered by theelectrical power supply to the second drive source is greater than orequal to a minimum electrical power.
 8. The air conditioning system ofclaim 7, wherein the at least one predetermined mode comprises anidle-stop mode.
 9. The air conditioning system of claim 7, wherein theat least one compressor further comprises: a first compression mechanismdriven by the first drive source; and a second compression mechanismdriven by the second drive source.
 10. The air conditioning system ofclaim 7, wherein the first drive source comprises an engine, the seconddrive source comprises an electric motor, and the electric power supplycomprises a battery.
 11. The air conditioning system of claim 7, furthercomprising: means for determining whether the vehicle is operating in anidle-stop mode; and means for determining whether the amount ofelectrical power delivered by the electrical power supply to the seconddrive source is greater than or equal to the minimum electrical power.12. The air conditioning system of claim 7, further comprising: anevaporator; and means for determining whether a temperature of airdispensed from the evaporator is greater than a predeterminedtemperature, wherein the at least one compressor is inactive when thetemperature of air dispensed from the evaporator is less than thepredetermined temperature, and the at least one compressor is activewhen the temperature of air dispensed from the evaporator is greaterthan or equal to the predetermined temperature.
 13. A vehiclecomprising: a first drive source; and an air conditioning systemcomprising: at least one compressor comprising a second drive source,wherein the at least one compressor is driven by the first drive sourceor the second drive source, or a combination thereof, and the seconddrive source comprises an electrical power supply; and means forselecting between the first drive source and the second drive source,such that when the at least one compressor is active, at least the firstdrive source drives the at least one compressor except when: the vehicleis operating in an idle-stop mode; and a voltage of the electrical powersupply is greater than or equal to a minimum electrical power supplyvoltage.
 14. The vehicle of claim 13, wherein the at least onecompressor further comprises: a first compression mechanism driven bythe first drive source; and a second compression mechanism driven by thesecond drive source.
 15. The vehicle of claim 13, wherein the firstdrive source comprises an engine, the second drive source comprises anelectric motor, and the electric power supply comprises a battery. 16.The vehicle of claim 13, further comprising: means for determiningwhether the vehicle is operating in an idle-stop mode; and means fordetermining whether the voltage of the electrical power supply isgreater than or equal to the minimum electrical power supply voltage.17. The air conditioning system of claim 13, further comprising: anevaporator; and means for determining whether a temperature of airdispensed from the evaporator is greater than a predeterminedtemperature, wherein the at least one compressor is inactive when thetemperature of air dispensed from the evaporator is less than thepredetermined temperature, and the at least one compressor is activewhen the temperature of air dispensed from the evaporator is greaterthan or equal to the predetermined temperature.
 18. A vehiclecomprising: a first drive source; and an air conditioning systemcomprising: at least one compressor comprising a second drive source,wherein the at least one compressor is driven by the first drive sourceor the second drive source, or a combination thereof, and the seconddrive source comprises an electrical power supply; and means forselecting between the first drive source and the second drive source,such that when the at least one compressor is active, at least the firstdrive source drives the at least one compressor except when: the vehicleis operating in at least one predetermined mode; and an amount ofelectrical power delivered by the electrical power supply to the seconddrive source is greater than or equal to a minimum electrical power. 19.The vehicle of claim 18, wherein the at least one predetermined modecomprises an idle-stop mode.
 20. The vehicle of claim 18, wherein the atleast one compressor further comprises: a first compression mechanismdriven by the first drive source; and a second compression mechanismdriven by the second drive source.
 21. The vehicle of claim 18, whereinthe first drive source comprises an engine, the second drive sourcecomprises an electric motor, and the electric power supply comprises abattery.
 22. The vehicle of claim 18, further comprising: means fordetermining whether the vehicle is operating in an idle-stop mode; andmeans for determining whether the amount of electrical power deliveredby the electrical power supply to the second drive source is greaterthan or equal to the minimum electrical power.
 23. The vehicle of claim18, further comprising: an evaporator; and means for determining whethera temperature of air dispensed from the evaporator is greater than apredetermined temperature, wherein the at least one compressor isinactive when the temperature of air dispensed from the evaporator isless than the predetermined temperature, and the at least one compressoris active when the temperature of air dispensed from the evaporator isgreater than or equal to the predetermined temperature.
 24. A method fordriving at least one compressor of an air conditioning system of avehicle, wherein the vehicle comprises a first drive source, and the airconditioning system comprises the at least one compressor, wherein theat least one compressor comprises a second drive source, and the seconddrive source comprises an electrical power supply, wherein the at leastone compressor is driven by the first drive source or the second drivesource, or a combination thereof, and the method comprises the steps of:determining whether the vehicle is operating in at least onepredetermined mode; activating the second drive source when the vehicleis operating in the at least one predetermined mode; and determiningwhether an amount of electric power consumed by the second drive sourceis greater than or equal to a maximum electric power switching the driveof the at least one compressor from the second drive source to the firstdrive source.
 25. The method of claim 24, wherein the at least onepredetermined mode comprises an idle-stop mode.
 26. The method of claim24, further comprising the steps of: deactivating the second drivesource when a voltage of the electrical power supply is less than aminimum electrical power supply voltage; and activating the first drivesource when the voltage of the electrical power supply is less than theminimum electrical power supply voltage.
 27. The method of claim 24,further comprising the steps of: deactivating the second drive sourcewhen an amount of electrical power delivered by the electrical powersupply to the second drive source is less than a minimum electricalpower; and activating the first drive source when the amount ofelectrical power delivered by the electrical power supply to the seconddrive source is less than the minimum electrical power.
 28. The methodof claim 24, wherein the at least one compressor further comprises: afirst compression mechanism driven by the first drive source; and asecond compression mechanism driven by the second drive source.
 29. Themethod of claim 24, wherein the first drive source comprises an engine,the second drive source comprises an electric motor, and the electricpower supply comprises a battery.